1. Field of the Invention
The present invention relates generally to a method for controlling the curling of metals. More specifically, this invention relates to a method of fabricating a metal device such as a hinge, wherein indentations are made in a metal work piece to control the curling aspect of the metal being worked on.
2. Description of Related Art
The related art of interest describes various methods and apparatus for bending metal workpieces, but none describes the present invention of forming specific indentations to improve the curling process. The related art will be discussed in the order of perceived relevance to the present invention.
U.S. Pat. No. 5,062,286 issued on Nov. 5, 1991, to Bengt I. G. Sjoblom describes a method and apparatus for bending a corrugated sheet transversely of the corrugations in which the valleys of the corrugated sheet are clamped against a die in an edging press device by tongues of a pressfoot while a fold line or weakening is pressed, in the form of an indentation into the corrugations' crests by a bar. The fold line or weakening enables the sheet to be subsequently bent to a desired angle over the edge of a bench or support surface. The method and apparatus are distinguishable for bending a corrugated metal sheet.
U.S. Pat. No. 5,051,294 issued on Sep. 24, 1991, to Michael J. Lunkas et al. describes a catalytic converter substrate and assembly formed of steel sheets embossed with corrugations in a chevron pattern such that the metal buckles at the vertices of the adjoining corrugations to form projections extending out of the plane of the sheet. The sheets are stacked with the projections registered to form weld points, and capacitive discharge welding secures the sheets together. The substrate is formed into two halves which are clamped together and secured by end rings. The catalytic converter substrate is distinguishable for forming vertices to buckle the corrugated sheet to form projections for weld points.
U.S. Pat. No. 4,380,573 issued on Apr. 19, 1993, to Gustav Naslund describes a method and device for bending section-sheet having corrugations of longitudinal and parallel ridges and valleys by introducing impressions transversely across the corrugated ridges. The method and device are distinguishable for treating only corrugated metal.
U.S. Pat. No. 1,197,271 issued on Sep. 5, 1916, to Ferdinand Dieckmann describes a method of producing sheet metal elbows from cylindrical, rectangular and corrugated metal pipes. Initially, a cylindrical metal pipe has hemispherical crimps made to form the elbow which is then processed by dies to form rectangular corrugated pipes. The method is distinguishable for preforming crimps in cylindrical pipes to form the elbow prior to subsequent forming of rectangular corrugated pipes.
U.S. Pat. No. 4,748,838 issued on Jun. 7, 1988, to Richard C. Cornelison describes a process for making obliquely corrugated thin metal strips by passing a thin metal strip through corrugating helical rolls for impressing a series of single apex, V-shaped chevron corrugations by which the strip can be split into two strips along the apices of the chevrons. The process is distinguishable for forming a chevron design for splitting a strip lengthwise.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.